To provide the power required to support the flight capabilities of helicopters, the main rotors of helicopters incorporate a plurality of main rotor blades having large radial dimensions. The large radial dimensions of helicopter rotor assemblies results in helicopters having large structural envelopes that occupy an inordinate amount of space. For example, an Apache helicopter, has a main rotor with four main rotor blades, a rotor diameter of approximately 48 feet (each main rotor blade has a length of approximately 21 feet), a fuselage length of approximately 49 feet, an overall length of approximately 58 feet and a height of nearly 17 feet. It is often desirable to reduce the structural envelopes of such helicopters to facilitate rapid deployment, routine transport, stowage, and/or to reduce the vulnerability thereof to environmental conditions. One way to reduce the structural envelopes of helicopters is to fold the main rotor blades relative to the rotor hub assembly (i.e., the main rotor assembly) such that the main rotor blades extend generally rearwardly relative to the rotor hub assembly.
It has been determined that it is desirable to support the main rotor blades relative to the helicopter during transportation of the helicopter. This has been accomplished with a tail boom saddle detachably secured to the tail boom of the helicopter. The main rotor blades are operatively connected to the tail boom saddle in a manner such that the main tail boom saddle maintains the main rotor blades in their folded configuration.
Generally, an assembly of the present invention comprises a helicopter and a tail boom saddle. The helicopter has a fuselage including a forward section and a tail boom section extending rearward of the forward section, a main rotor assembly extending out from the forward section of the fuselage, and a plurality of main rotor blades operatively coupled to the main rotor assembly. The tail boom section includes a first frame member, a second frame member longitudinally spaced from the first frame member, a plurality of longerons extending between and intersecting with the first and second frame members, and a tail boom outer skin surrounding the frame members and longerons. The longerons include first and second upper longerons. The main rotor blades are in a stowed position in which the main rotor blades extend generally rearwardly of the main rotor assembly. The tail boom saddle is detachably secured to the tail boom section of the helicopter. The main rotor blades are operatively secured to the tail boom saddle in a manner such that the tail boom saddle maintains the main rotor blades in the stowed position. The tail boom saddle has an upper saddle portion and a lower saddle portion. The upper and lower saddle portions exert clamping forces against the tail boom outer skin. The upper portion includes first and second support beams. The second support beam is laterally spaced from the first support beam. The first support beam is in engagement with an outer surface of the tail boom outer skin and extends generally along the first upper longeron from the first frame member to the second frame member. The second support beam is in engagement with the outer surface of the tail boom outer skin and extends generally along the second upper longeron from the first frame member to the second frame member.
Another aspect of the present invention is an assembly comprising a helicopter and a tail boom saddle. The helicopter has a fuselage including a forward section and a tail boom section extending rearward of the forward section, a main rotor assembly extending out from the forward section of the fuselage, and a plurality of main rotor blades operatively coupled to the main rotor assembly. The tail boom section includes a first frame member, a second frame member longitudinally spaced from the first frame member, a plurality of longerons extending between and intersecting with the first and second frame members, and a tail boom outer skin surrounding the frame members and longerons. The longerons include a first lower longeron. The main rotor blades are in a stowed position in which the main rotor blades extend generally rearwardly of the main rotor assembly. The tail boom saddle is detachably secured to the tail boom section of the helicopter. The main rotor blades are operatively secured to the tail boom saddle in a manner such that the tail boom saddle maintains the main rotor blades in the stowed position. The tail boom saddle has an upper saddle portion and a lower saddle portion. The upper and lower saddle portions exert clamping forces against the tail boom outer skin. The lower saddle portion comprises a lower saddle frame and at least one load distribution rocker mechanism operatively connected to the lower saddle frame. The rocker mechanism has a first tail-engaging pad and a second tail-engaging pad. The first tail-engaging pad is in engagement with the outer surface of the tail boom outer skin generally at the intersection of the first lower longeron and the first frame member. The second tail-engaging pad is in engagement with the outer surface of the tail boom outer skin generally at the intersection of the first lower longeron and the second frame member.
Another aspect of the present invention is a tail boom saddle for use with a helicopter. The helicopter has a fuselage including a forward section and a tail boom section extending rearward of the forward section, a main rotor assembly extending out from the forward section of the fuselage, and a plurality of main rotor blades operatively coupled to the main rotor assembly. The tail boom section includes a first frame member, a second frame member longitudinally spaced from the first frame member, a plurality of longerons extending between and intersecting with the first and second frame members, and a tail boom outer skin surrounding the frame members and longerons. The longerons include first and second upper longerons. The main rotor blades are movable to a stowed position in which the main rotor blades extend generally rearwardly of the main rotor assembly. The tail boom saddle comprises upper and lower saddle portions adapted to exert clamping forces against the tail boom outer skin. The tail boom saddle is adapted and configured to at least assist in maintaining the main rotor blades in the stowed position. The upper portion includes first and second support beams. The second support beam is laterally spaced from the first support beam. The tail boom saddle is configured and adapted such that the first support beam engages an outer surface of the tail boom outer skin and extends generally along the first upper longeron from the first frame member to the second frame member when the tail boom saddle is in a blade maintaining position and such that the second support beam engages the outer surface of the tail boom outer skin and extends generally along the second upper longeron from the first frame member to the second frame member when the tail boom saddle is in the blade maintaining position. The blade maintaining position is a position in which the upper and lower saddle portions exert clamping forces against the tail boom outer skin and the main rotor blades are operatively secured to the tail boom saddle in a manner such that the tail boom saddle maintains the main rotor blades in the stowed position.
Another aspect of the present invention comprises a tail boom saddle for use with a helicopter. The helicopter has a fuselage including a forward section and a tail boom section extending rearward of the forward section, a main rotor assembly extending out from the forward section of the fuselage, and a plurality of main rotor blades operatively coupled to the main rotor assembly. The tail boom section includes a first frame member, a second frame member longitudinally spaced from the first frame member, a plurality of longerons extending between and intersecting with the first and second frame members, and a tail boom outer skin surrounding the frame members and longerons. The longerons include a first lower longeron. The main rotor blades are movable to a stowed position in which the main rotor blades extend generally rearwardly of the main rotor assembly. The tail boom saddle comprises upper and lower saddle portions adapted to exert clamping forces against the tail boom outer skin. The tail boom saddle is adapted and configured to at least assist in maintaining the main rotor blades in the stowed position. The lower saddle portion comprises a lower saddle frame and at least one load distribution rocker mechanism operatively connected to the lower saddle frame. The rocker mechanism has a first tail-engaging pad and a second tail-engaging pad. The tail boom saddle is configured and adapted such that the first tail-engaging pad engages the outer surface of the tail boom outer skin generally at the intersection of the first lower longeron and the first frame member when the tail boom saddle is in a blade maintaining position and such that the second tail-engaging pad engages the outer surface of the tail boom outer skin generally at the intersection of the first lower longeron and the second frame member when the tail boom saddle is in the blade maintaining position. The blade maintaining position is a position in which the upper and lower saddle portions exert clamping forces against the tail boom outer skin and the main rotor blades are operatively secured to the tail boom saddle in a manner such that the tail boom saddle maintains the main rotor blades in the stowed position.
Other features and advantages will be in part apparent and in part pointed out hereinafter.